Definition of "tutress"

I offer ſubſcription; but always vnder reformation of that moſt honored Tutreſſes Pupils, which ſhall (omitting fabulous traſh) iudiciouſly inſtruct otherwiſe.

1612, [John Selden], “The Eleuenth Song. Illustrations.”, in Michael Drayton, edited by [John Selden], Poly-Olbion. Or A Chorographicall Description of Tracts, Riuers, Mountaines, Forests, and Other Parts of this Renowned Isle of Great Britaine, […], London: […] H[umphrey] L[ownes] for Mathew Lownes; I. Browne; I. Helme; I. Busbie, published 1613, page 192